Jess Carbajal's lawyer says his client 'is being thrown under the county bus.' Carlos Bustamante was charged last week with 12 felony counts in a sexual assault probe.

The Orange County public works director who supervised embattled former executive Carlos Bustamante has been fired, the first ranking official to be terminated in the wake of the politician's arrest on suspicion of sexual assault.

Public Works Director Jess Carbajal, 56, received a phone call informing him of his dismissal Tuesday morning and a letter later in the day, said his attorney, Wylie Aitken.

The move comes a week after Bustamante was charged with 12 felony counts in connection with the alleged sexual battery and false imprisonment of more than seven women over eight years.

Some of the alleged attacks occurred in Bustamante's office in the public works department. The women were working under Bustamante's supervision, prosecutors say.

Since the charges were filed, county supervisors have wondered who knew about Bustamante's alleged misdeeds. Last week, county supervisors called a special closed meeting to discuss the possible termination of Chief Executive Tom Mauk, but took no action.

Aitken said Carbajal was terminated by Mauk because he was Bustamante's supervisor.

"In reality, it appears that Mr. Carbajal is being thrown under the county bus," the attorney said.

Aitken said that in March 2011, Mauk instructed Carbajal to investigate allegations contained in two anonymous letters.

Mauk specified that the investigation be conducted "informally," Aitken said. Carbajal directed a human resources employee in the public works department to look into the charges, but after interviewing several workers, the woman could not substantiate the claims. No action was taken as a result of the investigation, Aitken said, but Carbajal was not in a position to discipline Bustamante without Mauk's consent.

"He did everything he was asked to do in looking into that initial anonymous complaint," Aitken said of his client.

Last fall, an anonymous letter and a call to the county's fraud hotline triggered more probes. Bustamante was placed on paid administrative leave Sept. 13 and resigned Oct. 4, but continued to receive three months of severance pay, according to the county human resources department. Bustamante is currently a Santa Ana city councilman.

In March, Carbajal was placed on paid administrative leave.

County spokesman Howard Sutter said in an email that Carbajal, who started working for the county in November 1999, was terminated with cause, which does not entitle him to a severance package. Carbajal earned $177,799 in the 2010-11 fiscal year, according to records.